Abstract:
An uncooled microbolometer pixel for detection of electromagnetic radiation is provided that includes a substrate, a thermistor assembly and an absorber assembly. The thermistor assembly includes a thermistor platform suspended above the substrate, one or more thermistors on the thermistor platform, and an electrode structure electrically connecting the thermistors to the substrate. The absorber assembly includes an optical absorber over the thermistor assembly and a reflector provided under and forming a resonant cavity with the optical absorber. The optical absorber is in thermal contact with the thermistors and exposed to the electromagnetic radiation. The optical absorber includes a set of elongated resonators determining an absorption spectrum of the optical absorber. An array of microbolometer pixels is also provided, in which the resonators of different pixels can have different lengths determining different absorption spectra, thereby enabling configurable broadband and/or multi-frequency detection, in particular in the terahertz region.
Abstract:
A microbolometer detector has an improved support structure. The microbolometer detector includes a substrate and a support structure including at least one post connected to and projecting substantially vertically from the substrate. The microbolometer detector also includes a platform held above the substrate and including a central region substantially vertically aligned with the at least one post of the support structure and a peripheral region surrounding the central region, the platform being supported by the support structure from the central region thereof. The microbolometer further includes at least one thermistor located in the peripheral region of the platform. A microbolometer focal plane array may also include multiple microbolometer detectors arranged in a two-dimensional array. The support structures are particularly well suited for supporting relatively large platforms of microbolometer detectors, particularly for far-infrared and terahertz detection and spectroscopy applications.
Abstract:
A microbolometer detector for detecting electromagnetic radiation is disclosed. The microbolometer detector includes a substrate, a vacuum package, and an array of microbolometers disposed on the substrate inside the vacuum package. Each microbolometer includes a platform supported above the substrate, a thermistor disposed on the platform and having an electrical resistance that varies with its temperature, and an optical absorber including a frequency-selective surface and configured to absorb the electromagnetic radiation to generate heat and change the temperature of the thermistor. The microbolometer detector also includes a reflector disposed on the substrate under the array of microbolometers, and an optical window configured to allow the electromagnetic radiation to pass therethrough and reach the optical absorbers. The optical window is spaced apart from the reflector to form therebetween an optically resonant cavity. The resonant cavity is tuned to an absorption band of the optical absorbers.
Abstract:
An uncooled microbolometer detector that includes a substrate, a platform held above the substrate by a support structure, at least one thermistor provided on the platform, and an optical absorber. The optical absorber includes at least one electrically conductive layer extending on the platform over and in thermal contact with the at least one thermistor and patterned to form a resonant structure defining an absorption spectrum of the uncooled microbolometer detector. The optical absorber is exposed to electromagnetic radiation and absorbs the electromagnetic radiation according to the absorption spectrum. A microbolometer array including a plurality of uncooled microbolometer detectors arranged in a two-dimensional array is also provided. Advantageously, these embodiments allow extending the absorption spectrum of conventional infrared uncooled microbolometer detectors to the terahertz region of the electromagnetic spectrum.
Abstract:
A microbolometer pixel unit for detection of terahertz radiation includes a substrate, a thermistor structure, and an optical absorber structure. The thermistor structure includes a plurality of microbolometer pixels disposed on the substrate. Each pixel includes a thermistor platform suspended above the substrate, a thermistor support member holding the thermistor platform, and a thermistor disposed on the thermistor platform and having an electrical resistance that varies in accordance with a temperature of the thermistor. The optical absorber structure includes an absorber platform suspended above the thermistor structure, an absorber support member holding the absorber platform and including a plurality of support elements, each support element providing a thermal conduction path from the absorber platform to the thermistor platform of a respective one of the microbolometer pixels, and an optical absorber disposed on the absorber platform to absorb incoming terahertz radiation to generate heat to change the temperature of the thermistors.
Abstract:
An imaging system that includes an image sensor and imaging optics is provided. The image sensor has a sensing surface and it captures images of a scene. The imaging optics is optically coupled to the image sensor and is configured to form the images of the scene onto the sensing surface of the image sensor. The imaging optics includes a sensor-adjacent optical element having an exit surface located in close proximity to the sensing surface of the image sensor. The exit surface of the sensor-adjacent optical element and the sensing surface of the image sensor are spaced apart by a gap having a gap width enabling evanescent-wave coupling from the exit surface to the sensing surface for light having wavelengths within the sensor spectral range.
Abstract:
Microbolometer detectors and arrays fabricated using printed electronics and photonics techniques, including ink-based printing, are disclosed. A microbolometer detector can include a substrate, a platform suspended above the substrate, and a thermistor printed on the platform and made of a thermistor material including an electrically conducting polymer, for example a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymeric composition. The microbolometer detector can also include an electrode structure electrically connected to the thermistor, and an ohmic contact layer interposed between the thermistor and the electrode structure. The electrode structure can be made of an electrode material including silver, while the ohmic contact layer can be made of an ohmic contact material including a PEDOT-carbon nanotube polymeric composition. A microbolometer array can include a plurality of microbolometer detectors arranged in a linear or two-dimensional matrix.